Androgen deprivation therapy may encourage prostate cancer cells to produce a protein that makes them more likely to spread, suggests Johns Hopkins’ researchers.
The team identified the problem after discovering that the gene that codes for the protein nestin was active in lab-grown human prostate cancer cells.
The researchers say that they found no nestin in cells from men who had surgery to remove the locally confined cancer. When they looked for nestin in prostate cancer cells isolated from patients who had died due to metastasis, however, they did identify substantial evidence that the nestin gene was active.
What was different, the investigators speculated, is that androgen deprivation therapy is generally given only when prostate cancers become aggressive and likely to metastasize.
The researchers then experimented on a prostate cancer cell line that depends on androgens to grow. When they removed androgens from the chemical mixture that the cells live in, production of nestin increased. Using RNAi to decrease the genetic expression of nestin, the Hopkins team found that these cells weren’t able to spread nearly as well as cells with normal nestin levels.
Prostate cancer cells with hampered nestin expression were also less likely than normal prostate cancer cells to migrate to other parts of the body when transplanted into mice, according to the scientists. While nestin expression seemed pivotal for metastasis in these experiments, however, it didn’t seem to make a difference in tumor growth.
The research is published in the October 1 issue of Cancer Research.